Source: Wikia, "http://rayman.wikia.com/wiki/Rayman_(game)," available under the CC-BY-SA License.
Originally the plot of Rayman was very different. Many magazines had things like: Join Jimmy, a 10-year-old who escapes reality by entering Hereitscool, a fantasy kingdom he has created within the realms of his computer. When an evil power takes over Hereitscool, Jimmy becomes Rayman, a super hero who must save his friends before it's too late! But it was scrapped for obvious reasons, and Rayman is his own being in his own world in the final version. There were a few comments in the story, such as "Sorry folks, this appearance can't last. Do you want to play or what?", but they were cut for the final version. It is because of this game that Ubisoft is as big as it is today.
Rayman is a traditional side-scrolling 2D platform game. The object of the game is to free all the electoons and defeat Mister Dark's minions across six worlds: Dream Forest, Band Land, Blue Mountains, Picture City, Cave of Skops, and Candy Chateau aka Mr darks lair. Only when every electoon is freed will Rayman be able to enter into Mister Dark's hideout in Candy Chateau. Otherwise, the player must traverse the levels and reach the goal (a signpost with an exclamation mark on it) at the end. But usually, since all of the levels in the game are divided into several parts, said goal post usually acts as a transition to another part of the level.
Rayman will come across a variety of other power-ups and bonuses, among which a golden punching fist, a faster punching fist, power to restore Rayman's lost life energy and flying blue elves that will shrink Rayman down in size.